Terminal post and testing tool



F. KASTEL Feb. 20, 1968 TERMINAL POST AND TESTING TOOL Filed Oct. 2l, 1965 l! A* S IIC INVENTOR.

Kostel Fred United States Patent 3,370,139 TERMINAL POST AND TESTING TOOL Fred Kastel, 3434 Edison St., San Mateo, Calif. 94403 Filed Get. 21, 1965, Ser. No. 500,061 9 Claims. (Cl. 200-51.1)

ABSTRACT F THE DISCLOSURE A binding post is constructed so that normally contact between two wires leading to the post is established by resilient means. A tool cooperates with a portion of the post to separate electrical connection between the two wires and simultaneously uninterruptedly to establish connection with wires leading to a test tool.

This invention relates to a new and improved terminal post and testing tool. Reference is made to copending application Serial No. 283,186, filed May 27, 1963, entitled Test Probe Entry Connector, no'w Patent 3,248,495.

It is conventional practice in wiring electrical circuits t0 provide a non-conductive board from which project one or more terminal or binding posts. The ends of the wires are electrically connected together by compressing said ends between the board and a nut threaded over the binding post, or by somewhat more elaborate means. The present invention provides such a binding post or terminal which normally establishes contact between two or more wires leading to the post. In essence, the present invention provides a binding post construction and a tool construction cooperable with the post to separate the two wires or two parts of a circuit from electrical connection with each other simultaneously without interruption or measurable change to establish a connection between each of two wires, or each side of a circuit, and one terminal or probe of a testing tool. Accordingly, if the probes of the testing tool are connected to an ammeter or current coil of other measuring or recording instruments the current fiowing, together with its waveform, through the circuit may be tested. Similarly, electrical components both passive and active may be inserted into the circuit. The use of additional setups of this invention will give more complex multiple uses such as involved in 2wire land 4- wire circuit analysis and synthesis. Thus the present invention eliminates the necessity of cutting or disconnecting the wire in order to insert the probes of the test instrument, or conductors of the components.

Another feature of the invention is the fact that the establishment of contacts with the test probes occurs prior to the electrical separation of the two wires (or noninterruption of two parts of a circuit where more than two wires are involved at the terminal) so that momentary opening of a circuit with the often serious results of equipment failure or erroneous operation from the transient or pulse introduced is eliminated.

Another important feature and advantage of the present invention is the fact that the probe is held and applied relative to the binding post co-aXially. This feature reduces the space required for the contactor feature and binding post which are combined in the present invention and eliminates the necessity of a separate contactor device adjacent the binding post by incorporating the two elements along a single aXis.

A particular advantage of the present invention is its simplicity of construction and of operation whereby by simply twisting the tool relative to the binding post the circuit between the two wires, or among more than two wires, may be transferred through the test probes two wires with a new circuit established as desired.

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An additional advantage of the present invention is the ease and rapidity of entering a 2-wire or 4-Wire communication circuit by twisting on two or four tools on the appropriate binding posts.

Another feature of the invention is that it may be added, with only minor modification, to existing terminal strips with various terminal screws or binding posts with consequent great economy and flexibility in operation and maintenance of electrical equipment not previously available.

The interconnection of one or more tools provides patching cord facilities, such as terminations, attenuation, bridging and switching of circuits.

As an optional feature, the post and tool may be formed with mutilated threads so that in one alignment of the two elements they move relative to each other in an axial direction toward engagement. Then by twisting the tool through a short angular movement-eg., slightly less than -the tool moves to transfer the circuit to the test probes. This form of the invention improves the rapidity and convenience of operation.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

FIG. 1 is an exploded side elevational view, partly broken away in section, of a binding post and tool in accordance with the present invention.

FIG. 2 is a longitudinal sectional assembled view of the elements of FIG. l. A

FIG. 3 is an exploded perspective view of certain of the elements of FIGS. 1 and 2.

FIG. 4 is a view similar to FIG. 1 of a modification.

FIG. 5 is a view similar to FIG. 2 of the modification of FIG. 4.

FIG. 6 is a side elevational view of a portion of the structure of FIGS. 4 and 5.

FIG. 7 is a bottom plan of a modified tool.

FIG. 8 is a top plan of a modified binding post nut used in conjunction therewith.

In the modification of FIGS. 1-3, there is provided a terminal board 11 of nonconductive material which may be formed on one surface with a boss 12. An aperture 13 is formed therein and a noncircular counterbore 14 on the bottom surface. Fitting through aperture 13 is an elongated binding screw 16 having a noncircular head 17 fitting within counterbore 14. Accordingly, screw 16 is nonrotative relative to nonconductive board 11. To secure screw 16 in place, a nut 18 is threaded over screw 16 and preferably a thin Iwasher 19 is interposed between nut 18 and boss 12 to facilitate assembly and disassembly.

The primary purpose of the binding post construction is to establish 'a detachable electrical connection between wires 21 and 22. For convenience of assembly, said wires 21, 22 are connected through connecting eyes 23 with washer-like conductive members 24. 26 or first and second contacts respectively, the eyes 23 being formed integrally with members 24, 26 or connected thereto. Washer 24 has a circular hole which fits over screw 16. Washer 26 a noncircular cent1-'al hole 27, the purpose of the noncircular shape being hereinafter explained. The size o`f aperture 27 is greater than the hole in washer 24.

Washer 24 is held in place on post 16 by means of a second nut 28, there preferably being a thin washer 29 interposed Iabove washer 24. Above nut 28 and surrounding post 16 is a nonconductive sleeve 31 having a flange 32 at its base. The upper end of sleeve 31 is formed with ats 33 to receive the aperture 27 of washer 26 in nonrotative manner. A relatively stiff coil spring 34 surrounds sleeve 31 and rests on base ange 32 and bears 'against washer 26 normally biasing said washer into electrical contact with third nut 36 or abutment which is also threaded on binding post 16 above sleeve 31. In`- asmuch as washer 26 is normally in electrical contact with nut 36 and hence with post 16, as shown in FIG. l, the circuit between conductors 21 and 22 is normally closed.

Above nut 36 on post 16 is a fourth nut 37 having a reduced diameter externally threaded upward extension or conductive element 38. The pitch of the threads on extension 38 is considerably greater than on post 16 for a purpose which hereinafter appears.

Tool 41 is used to separate contact between conductors 21 and 22. For such purpose there is provided a nonconductive casing 42 having at its lower end a bore 43 of a diameter greater than the external diameter of nuts 36, 37. In the bottom of bore 43 is a conductive fitting or conductive element 44 having at its lower end a threaded portion 46 which mates with the threads of portion 38. Surrounding the lower end of bore 43 and recessed into the bottom of casing 42 is a conductive ring or conductive element 47 which is of a diameter such as to engage washer 26 in the operative position of tool 41. Fitting 44 is connected by means of screw 47 to probe lead 48 which extends outside of tool 41. Similarly, ring 47 is connected by lead 49 and screw 51 to probe lead 52 which also leads exteriorly of casing 41, 42. Leads 48, 52 may be connected to an instrument 53 such as an ammeter.

The use of tool 41 is as follows: When it is desired to determine the current passing through leads 21, 22, tool 41 is positioned axially above binding post 16 and lowered until the threaded end 38 of nut 37 engages threads 46 of fitting 44. By reason of the pitch of threads 38 and post 16, a twist of tool 41 a few degrees depresses tool 41 relative to board 11. As tool 41 is depressed, ring 47 depresses washer 26 breaking contact between washer 26 and nut 36 as is shown in FIG. 2. Accordingly, direct connection between leads 21 and 22 is interrupted. At the same time, fitting 44 establishes contact with nut 37 and binding post 13 and hence with lead 21. Meanwhile ring 47 establishes contact with washer 26 and hence lead 22. Probes 48, 52 thus are connected through meter 53 to read the current passing between leads 21, 22. Thus the tool by a simple axial and short twisting movement interrupts direct communication between leads 21 and 22 and enables a meter reading relative to the two conductors to be quickly obtained. As soon as the tool 41 is turned back to its original position, downward pressure on w'asher 26 is released and spring 34 returns washer 26 to direct contact with nut 36 and restores communication between leads 21, 22.

The modification of FIGS. 4 t0 6 resembles that of the modification of FIGS. 1 to 3 in many details and corresponding parts are designated by the same reference numeral followed by the subscript a. It is conventional practice at the present time in some installations to install on the upper end of binding post 16a a nonconductive nut 56. Where a plurality of binding posts is installed in close proximity, the presence of nonconductive nut 56 prevents accidental shorting between adjacent binding posts and consequent damage. Nut 56 is modified from conventional nuts in accordance with the present invention by forming an opening for bore 57 centrally therein and installing a centrally internally threaded conductive fitting 58 which is in threaded engagement with post 16a. in normal operation. Fitting 58 is annular and has an enlarged diameter upper end 59 through which fits a transverse conductive pin 61.

Tool 41a differs from tool 41 of the preceding modification in that its lower end has a plurality of downward extending segments or portions 62 hinged to the upper portion of casing 41a by means of ears 63y and hinge pins 64. The lower ends of segments 62 are biased inwardly by spring 66 to normally assume the position shown in FIGS. 4 and 5. Ring segments 67 are recessed into the lower end of each segment 62 to establish conJ tact with Washer 26a as is best shown in FIG. 5. Thus when the tool 41a is installed, it is pushed downwardly and by reason of the fact that the surface `68 of nut 56 slants downwardly outwardly the segments 62 are forced outwardly around the outside of nut 56 and as the tool is brought further down the spring 66 restores the segments to original position with ring segment 67 in electrical contact with washer 26a. Further, as the tool 41a is depressed, the lower ends of segments 62 and ring segments `67 depress washer 26a as in the preceding modiiication.

To provide for depression washer 26a 'a special fitting 71 is installed on the lower end of stern 72 threaded into casing 42a. Fitting 71 has helicalslots 73 as best shown in FIG. 6 to receive pin 61. As tool 41a is twisted and depresesd, a pin 61 enters slots 73 and continued turning movement depresses pin 71 and hence tool 41a relative to binding post 16a. Depression of the tool thus causes washer 26a to be depressed and this disconnects electrical engagement between washer 26a and nut 36a as is best shown in FIG. 5.

Since the ring segments 67 'are connected to lead wire 48a and since stem 712 is connected to lead wire 52a, when electrical contact between washer 26a and nut 36a is interrupted, the leads 48a and 52a are electrically connected to conductors 22a and 21a, respectively, as in the preceding modification.

It will thus be seen that even though a nonconductive nut 56 or other fitting is installed on the upper end of binding post 16a' for the purpose heretofore described, nevertheless the tool may be used to interrupt the circuit and to establish contact between the two conductors and the electrical probes 48a, 52a exactly as in the preceding modification and with similar results. The modification of FIGS. 4-6 is readily attached and detached by an axial depression and twisting movement as has heretofore been explained.

The modification partially illustrated in FIGS. 7 and 8 is of an even more rapid connecting and disconnecting construction. In most particulars, the construction resembles that of FIGS. 1 to 3, and corresponding parts are designated with the same reference numeral followed by subscript b. In this form of the invention, the extension 38h is formed with an external mutilated thread, i.e., diametrically opposed flats 81 are cut :into the otherwise round cross-section of extension 38b. Similarly, the ,interiorly threaded lower end 46b of fitting 44b is cut away or multilated in diametrically opposed enlargements 82. When fiats 81 and enlargements 82 are aligned at 909 relative to each other, tool 41b can be moved axially relative to nut 37b (and the binding post on which it is installed) until ring 4711 contacts member 26 (not shown in FIGS. 7 and 8 but similar to the corresponding ele` ment in the preceding modifications). Then by turning -tool 41b through an angle of less than 180, threads 3811 and 4617 engageA and cause axial movement diverting the current to the test probes. The operation can be reversed either by turning tool 41b in the same direction through the remaining angular movement to complete a total of or by turning tool in the opposite direction back tot its original angular position. In either event, threads 38b, 4611 disengage and the tool can be removed.

Although the foregoing invention has been described in some detail, by Way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be practiced within the spirit of the invention and scope of the appended claims.

What is claimed is:

1. In combination, a binding post, having a stern, a first contact, means xing said first contact on said stern, a second contact supported on said stem and slidable relative to said stern, an abutment fixed on said stem remote from said first contact, said stem, first and second contacts and abutment being electrically conductive, resilient means supported by said stem for biasing said second contact into electrical communication with said abutment to establish an electrical circuit between said contacts; and a tool formed with a cavity fitting over said post, said tool shaped to engage said second contact and force said second contact away from said abutment to interrupt said circuit, said tool having a first conductive element formed to engage said second contact and a second conductive element, said stem having a third conductive element positioned to be electrically engaged by said second conductive element, said second and third conductive elements being mechanically cooperable when engaged to move said tool relative to said post to force said second contact away from said abutment, said tool formed with an opening at one end to receive an end of said post, said opening smaller than said second contact, said first conductive element smaller than said second contact and around said opening, said third conductive element smaller than said opening, said second conductive element inside said opening, said second and third conductive elements being threaded whereby turning said tool moves said tool relative to said post,

2. A binding post construction having an elongated stem, a first contact fixed supported on the bottom of said stem, a second contact apertured to receive said stem and slidable along said stem toward and away from said first contact, an abutment fixed adjacent the top of said stem remote from said first contact, a helical spring supported on said stem for biasing said second contact into electrical communication with said abutment to establish an electrical circuit between said contacts, said stem, said contacts and said abutment being electrically conductive, a fitting on the top of said stern adapted for threaded engagement with a cooperable external second fitting for movement of said second fitting axially of said stem upon relative turning movement of said fitting out of electrical contact with said abutment, and a nonconductive sleeve around said stem between said first contact and said abutment, said spring around the exterior of said nonconductive sleeve.

3. The combination of claim 1 in which said second and third conductive elements are threaded whereby turning said tool moves said tool relative to said post.

4. A tool for the purpose described comprising a body formed with a cavity opening at one end of said tool, a first electrical conductive element on said one end of said body around said opening, a second conductive element in the interior of said cavity, a plurality of portions at one end of said body, mounting means connecting said portions to said body for movement between a contracted first position defining said opening and an expanded second position enlarging said opening, and means biasing said portions toward first position.

5. In combination, a binding post, having a stern, a first contact, means fixing said first contact on said stem, a second contact slidable relative to said stern, an abutment fixed on said stem remote from said first contact, said stern, first and second contacts and abutment being electrically conductive, resilient means biasing said second contact into electrical communication with said abutment to establish an electrical circuit between said contacts; and a tool formed with a cavity fitting over said post, said tool shaped to engage said second contact and force said second contact away from said abutment to interrupt said circuit, said tool having a first conductive element formed to engage said second contact and a second conductive element, said stem having a third conductive element positioned to be electrically engaged by said second conductive element, said second and third conductive elements being mechanically cooperable when engaged `to move said tool relative to said post to force said second contact away from said abutment, said tool formed with an opening at one end to receive an end of said post, said opening smaller than said second contact, said first conductive element smaller than said second contact and around said opening, said third conductive element smaller than said opening, said second conductive element inside said opening, said second and third conductive elements 'being threaded whereby turning said tool moves said tool relative to said post, the threads of said second and third conductive elements being mutilated for extensive axial movement relative to each other in one angular position and for threaded engagement in another angular position.

6. In combination, a binding post, having a stem, a first contact, means fixing said first contact on said stem, a second contact slidable relative to said stem, an abutment fixed on said stem remote from said first contact, said stem, first and second contacts and abutmentl being electrically conductive, resilient means biasing said sec ond contact into electrical communication with said abutment to establish an electrical circuit between said contacts; and a tool formed with a cavity fitting over said post, said tool shaped to engage said second contact and force said second contact away from said abutment to interrupt said circuit, said tool having a first conductive element formed to engage said second contact and a second conductive element, said stem having a third conductive element positioned to be electrically engaged by said second conductive element, said second and third conductive elements being mechanically cooperable when engaged to move said tool relative to said post to force said second contact away from said abutment, said tool formed with an opening at one end to receive an end of said post, said opening smaller than said second contact, said first conductive element smaller than said second contact and around said opening, said third conductive element smaller than said opening, said second conductive element inside said opening, said stem carrying an enlarged nonconductive member of said abutment and carrying said third conductive element, said tool having pivotally mounted portions defining said opening arranged to pivot outwardly to permit said nonconductive member to be received inside said opening with said second and third conductive elements to be electrically and mechanically engaged and said first conductive element and second contact to be electrically engaged, said tool fitting against said second contact and sliding same along said post away from said abutment.

7. A binding post construction having an elongated stem, a first contact fixed to said stem, a second contact on said stem slidable relative to said stem, an abutment fixed on said stem remote from said first contact, resilient means biasing said second contact into electrical cornmunication with said abutment to establish an electrical circuit between said contacts, said stem, said contacts and said abutment being in electrical communication, a fitting on an end of said stem adapted for threaded engagement with a cooperable external second fitting for movement of said second fitting axialy of said stem upon relative turning movement of said fitting, and a nonconductive sleeve around said stem between said first contact and said abutment, said second contact apertured to receive said stem.

8. A binding post construction having an elongated stem, a first Contact fixed to said stem, a second Contact on said stem slidable relative to said stem, an abutment fixed on said stem remote for said rst contact, resilient means .biasing-said second contact into electrical communication with said abutment to establish an electrical circuit between said contacts, said stem, said contacts and said abutment being in electrical communication, a fitting on an end of said stem adapted for threaded engagement with a cooperable external second fitting for movement of said second tting axially of said stem upon relative turning movement of said fitting, said resilient means Ibeing a helical spring around said sleeve and said sleeve having a nonconductive enlargement engaged by one end of said spring, the other end of said spring engaging said second Contact.

9. A tool according to claim 4, in which said rst conductive element is received into the lower end of at least one said portion.

References Cited UNITED STATES PATENTS 2,713,102 7/1955 Lavarack ZOO-158 8 617,464 1/1899 Holmes 20G-51.1 2,732,446 1/1956 Gilmore ZOO- 51.1

FOREIGN PATENTS 564,922 10/ 1923 France. 691,333 5/ 1940 Germany.

ROBERT K. SCHAEFER, Prmmy Examiner.

D. SMITH, Assistant Examiner. 

